Index: includes/install.core.inc
===================================================================
--- includes/install.core.inc	(revision 7)
+++ includes/install.core.inc	(working copy)
@@ -1194,7 +1194,8 @@
         }
         else {
           include_once DRUPAL_ROOT . '/includes/form.inc';
-          $output = drupal_render(drupal_get_form('install_select_locale_form', $locales, $profilename));
+          $form = drupal_get_form('install_select_locale_form', $locales, $profilename);
+          $output = drupal_render($form);
         }
         return $output;
       }